Battery Tender question

[Socal Cherokee]

It looks like the 12V, 5 amp Battery Tender is in short supply. It's received great reviews but won't be back on the shelves for weeks. The 12V, 1.25 amp model is plentiful however.
I'm looking for a smart charger, but for my meager use and recharging demands, I'm thinking the 1.25 amp model should be good enough. The batteries will have plenty of time to recharge between weekend getaways, so a speedy recharge is not really needed.

Any differences between the two models that I'm missing? Should I hold off for the 5amp model?

Thanks for the help!

-Ron

[james tillitt]

I bought my 1.25 amp model about six years ago for my Ducati motorcycle that came with a bad battery. The "new" battery that came with the bike lasted about two month's before it was too low to start the bike, so I got the battery tender and had it plugged into the bike (which wasn't run for months in the winter) for the next five years with no problems. I think the 1.25 amp model will work fine for most TD applications.

[madjack]

I have the 5a model on order...they are supposed to ship on the 9th of Nov...about 3 weeks...the difference is in the charge rate...if you have plenty of battery to meet your needs while camping and enough time betwen trips for the smaller unit to work, then good for you...I plan on using the 5a model as a "convertor" hooked up over the battery to provide all needed 12v power.................
madjack

[Arne]

I use the battery tender jr, with .75 amps.. I run lights and fan and it always recharges overnight... I don't recommend it because if I have to go several days without recharging it might take more than one night to charge..

I think for most purposes in a tear, the 1.25 should be ok. I run a dome light, 2 reading lights and a fantastic fan off my deep cycle.. at home, the charger is always plugged in..

I've used one on my motorcycle since I got it in 2002 and am still on the original battery.

[tonyj]

Sorry if I hijack here, but it is in line with the subject.

I have the battery tender 5 amp and I am trying to figure out a fix to a problem. The units seems to be cooking the battery. The battery is a group 27 Interstate deep cycle.

I got to the barn a couple months back to find the battery dead (read 0 volts!) and the battery tender off. Water level in the battery okay. Put the battery on another charger--it cycled to max and turned off immediately. I suspected an open in the battery. I put another battery on the tender and discovered it was charging at 16-1/2 volts.

I called Battery Mart and they sent me a new tender. I took the battery back to Interstate, they charged the battery (I was surprised) and tested it out and pronounced it okay.

I reinstalled the new tender and the battery. The unit charges at a little over 14 volts, like it should, but goes into the deep charge mode for well over 36 hours (battery tender instructions say deep cycle batteries may take up to 18 hours to fully charge). By the time the charger gets to maintenance mode, it has boiled most the water from the battery. I've checked the battery--voltage good and holds for days with little loss when not connected to the charger, and all cells are in the same range when hydrometer checked.

I have been trying to decide if I should just replace the battery with an non-venting battery (Optima) since the charge on this battery is creating vast amount of fumes. My other option is to replace the tender with the 1.25 amp model.

Any thoughts?

[jplock]

tonyj,
I have the same setup you do. I have the 5 amp charger and a Interstate Deep Cycle battery as you do. It is left hooked up all the time charging/maintaining 24/7. There has been no problems. I wonder if your charger may be defective.
jplock

[halfdome, Danny]

Tony, I also have the same charger and have had some problems that are different and not the chargers fault. I have 2 batteries that are a year apart in age and the charger would keep charging until the older one was fully charged. That would make the new one over charge. Today I removed the year old battery and replaced it with the same brand, month & year as the other one which is Aug 2007. One day I was trying to figure out a porch light problem and popped the fuse. Then I noticed my voltmeter that plugs into the lighter plug was reading 19.5 volts. It said the same in the tow vehicle so I bought a new one @ Walmart and now my readings are normal. Could it be possible your voltmeter is faulty? Just a thought. Danny

[Alphacarina]

I have been trying to decide if I should just replace the battery with an non-venting battery (Optima) since the charge on this battery is creating vast amount of fumes. My other option is to replace the tender with the 1.25 amp model.

Any thoughts?

You have one or more problems

Obviously, the original charger had a problem and that certainly didn't do the battery any good - I'm really surprised that any battery which read zero volts 'came back from the dead' - Usually a long gone battery which is completely sulfated will read something - 3 or 4 volts at the least. I would be suspect of your battery

Lead acid batteries 'self discharge' when just sitting and not connected to anything at a rate of 15% or 20% per month, so if they sit long, they need to be connected to a trickle charger of some sort. Even then, they are not a really good choice for equipment which only gets used 3 or 4 times per year and sits for months at a time between uses. Any wet cell which is held at an elevated voltage (like is the case when permanently connected to a trickle charger) will gas and slowly consume water so you need to check and replentish the water every 90 days or so

AGM batteries are quite another matter - They self discharge much, much slower (on the order of 3% to 5% per month) so they can sit for several months with no charger connected to them and then be given a couple hour top off charge before you leave. AGM's are a much better choice for equipment which is infrequently used

I predict that if you buy an AGM for your tear, you will be impressed and satisfied

Don

[tonyj]

Phil--I would suspect the charger, but it I can't believe I would get a second bad charger (yes, I know it is possible). I spent one full weekend monitoring the battery and charger, adding water and just letting it charge. I was on charge close to 48 hours before the charger went to float mode.

Danny, I don't think it is the voltmeter. When the charger was showing hi voltage, I checked another battery to check the reading on the voltmeter and it was 12.4 volts.

Don--thanks. I'm sure I will someday go to an AGM battery, but now I am determined to get more mileage from the one I have.

In fact, I may just go buy the least expensive deep cycle wet cell I can find. If it does turn out to be the charger, I'm out less cost than if I paid the big bucks for an Optima.

For now, and until I go to LCG and Inks, I'll just charge up the battery, then unplug the charger so I don't fry the batter. I had the two hatch lights and radio on most the weekend and it wasn't until this afternoon that I could tell the battery was losing charge.

Thanks for the ideas, and for letting me hijack this post.

[halfdome, Danny]

I just had a long talk with one of the tech guys at Battery Mart about my Battery Tender. I've been noticing my voltmeter reads a little higher every day and it got up to 17.10 volts. He said what I'm seeing is the current of the Battery Tender in the float mode and the charge on the batteries and it's okay. He had me unplug the Battery Tender and said it should settle down into the 14 volt range. In a couple minutes I ended up with 14.03 volts for both batteries, which is just fine. He did mention that if you keep your battery always on the Battery Tender it's a good idea to unplug it a couple times a month to let it cycle but don't go below 12 volts. Danny

[emiller]

Thanks Danny good to know, I have that same one jplock is showing.

[brian_bp]

I just had a long talk with one of the tech guys at Battery Mart about my Battery Tender. I've been noticing my voltmeter reads a little higher every day and it got up to 17.10 volts. He said what I'm seeing is the current of the Battery Tender in the float mode and the charge on the batteries and it's okay. He had me unplug the Battery Tender and said it should settle down into the 14 volt range. In a couple minutes I ended up with 14.03 volts for both batteries, which is just fine....

This makes no sense to me. If it is really in float mode, the voltage would be at the float level, much less than 17 volts. If the voltage is climbing, the charger is putting out too much voltage.

It sounds like the charger was in charge (not float) mode, and when unplugged and reconnected it saw a high enough battery voltage that it actually went into float mode.

The point of a "battery tender" is that you don't have to tend to it yourself, by resetting it twice a month. If you're going to do that, you might as well use any "smart" charger to do one charge cycle each semi-monthly cycle, and leave it on a plain float supply the rest of the time... or just leave it disconnected between charges, because batteries can go two weeks without a tender.

[Alphacarina]

I agree - If I ever saw 17 volts on my battery's terminals, the tender would be in the trash 5 minutes later . . . . and the battery probably not soon after, because floating at 17 volts is absolute death for the battery

Don

[halfdome, Danny]

This makes no sense to me. If it is really in float mode, the voltage would be at the float level, much less than 17 volts. If the voltage is climbing, the charger is putting out too much voltage.

It sounds like the charger was in charge (not float) mode, and when unplugged and reconnected it saw a high enough battery voltage that it actually went into float mode.

The point of a "battery tender" is that you don't have to tend to it yourself, by resetting it twice a month. If you're going to do that, you might as well use any "smart" charger to do one charge cycle each semi-monthly cycle, and leave it on a plain float supply the rest of the time... or just leave it disconnected between charges, because batteries can go two weeks without a tender.

Brian, maybe you should call Battery Mart.com and talk to them. Telephone: 1-800-405-2121 or 540-665-0065 Fax: 540-665-9623
Let me know what you learn from them, please. My Battery Tender has been in float mode all week and I know that for a fact since we sleep in the TD. Every time I get up in the night I check the voltmeter and I'll go over and feel which light is on. Believe me it was in float mode. He was saying to let it cycle for the health of the battery. When I had the smaller Battery Tender my voltage always stayed in around 14 volts. One reason to have a 5 amp model is what Madjack stated & that's partially why we have one. Danny

I plan on using the 5a model as a "convertor" hooked up over the battery to provide all needed 12v power.................
madjack

[halfdome, Danny]

Battery Mart's response to my email:
Danny
I spoke to you on the phone yesterday. I placed a call to a Deltran Tech. He advised the charger output may be a little on the high side. Based on this, it would probably be best if you sent the charger in and let our Tech's check it. I have included an RA# below, and copy of your order. Please send your charger back to us using the below RA#. Please put the RA# on the outside of the shipping package and send it back to the below address. Please packaged the charger as to avoid and damage during the return shipping. We suggest sending the charger insured as BatteryMart is not responsible for any damage or loss during the return shipping.
Please Note: These charges are currently on back order with Deltran and if the charger is found to be defective, the earliest we could send a replacement is estimated to be November 12th.